RU2234794C1 - Sine-wave voltage oscillator - Google Patents

Abstract

FIELD: electronic engineering; continuous-wave oscillators.

SUBSTANCE: oscillator has input device 1, band filter 2, operational amplifier 3, threshold element 4, first and second flip-flops 5 and 6, respectively, first and second analog switches 7 and 8, respectively, resistor 9, capacitor 10, field-effect transistor 11, positive and negative power supplies 12 and 13, respectively. Output signal phase stability is attained due to ability of comparing voltage phase at input and output of band filter and generating differential signal that tunes band filter at constant magnitude of output signal.

EFFECT: enhanced stability of oscillator output voltage phase.

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Description

The invention relates to the field of electronic technology and can be used as a generator of undamped sinusoidal oscillations.

Known bridge generator [1] containing an operational amplifier, an R-C chain, a diode rectifier, a field effect transistor.

The disadvantage of this device is a sufficiently large (about 2 s) time to establish the amplitude of the output voltage.

Also known is a sinusoidal voltage generator [2], comprising a series-connected input circuit, a bandpass filter, an operational amplifier, a rectifier, a low-pass filter, a threshold element, a diode connected to the midpoint of the series-connected resistors connected between the input device and the bandpass filter.

The disadvantage of this device is the insufficiently high phase stability between the output and input voltage of the generator.

The problem to which this invention is directed is to increase the phase stability of the generator output voltage.

The problem is achieved in that a sinusoidal voltage generator containing a series-connected input circuit, the input of which is the input of the device, a bandpass filter, an operational amplifier, the output of which is the output of the device, and a threshold element, additionally introduced the first and second analog keys, the first and second triggers, a resistor, a capacitor and a field effect transistor, connected by a drain and a source to the frequency-determining circuit of a band-pass filter, and by a gate through a capacitor to a common bus and through a cut a source to the midpoint of the first and second analog keys connected in series, connected between the positive and negative power sources of the device, and the control inputs of the keys are connected respectively to the outputs of the first and second triggers, the S-input of the first trigger is connected to the R-input of the second trigger and connected to the output threshold element, and the S-input of the second trigger is connected to the R-input of the first trigger and connected to the input of the bandpass filter.

Significant differences between the claimed device and the known one include the introduction of two analog switches, two triggers, a resistor, a capacitor and a field effect transistor. The introduction of the above elements made it possible to increase the phase stability of the output signal by obtaining the possibility of comparing the phase of the voltage at the input and output of the band-pass filter and to obtain a difference signal that tunes the band-pass filter in order to match the phases with a constant output signal.

The drawing shows a structural diagram of a device.

The proposed sinusoidal voltage generator contains an input device 1, a bandpass filter 2, an operational amplifier 3, a threshold element 4, the first and second triggers 5 and 6, the first and second analog switches 7 and 8, a resistor 9, a capacitor 10, a field effect transistor 11, positive and negative 12 and 13 power supplies, input 14, output 15.

The input of the input device 1 is the input 14 of the device, the output is connected to the input of the bandpass filter 2, its output is connected to the input of the operational amplifier 3, the output of which is the output 15 of the device and connected to the input of the threshold element 4, the output of which is connected to the S-input of the first trigger 5 and R-input of the second trigger 6. The outputs of the triggers 5 and 6 are connected respectively to the control inputs of the analog keys 7 and 8, connected to the positive 12 and 13 negative power sources. The midpoint of the connection of the keys 7 and 8 is connected through a resistor 9 to the gate of the field effect transistor 11 connected through a capacitor 10 to a common bus, and the drain and source to the frequency-determining circuit of the bandpass filter 2.

The device operates as follows.

A sequence of rectangular pulses is fed to the input 14 of the device and, through the input circuit 1, is fed to the input of the bandpass filter 2, where the first harmonic is selected, which has a sinusoidal shape, which is fed to the input of the operational amplifier 3, the output of which is the output 15 of the device, and to the input of the threshold device 4 At the output of the threshold device 4, rectangular pulses are formed, the frequency and phase of which coincide with the output sinusoidal voltage. These pulses are fed to the inputs S and R of the first and second triggers 5 and 6, respectively, to the R and S inputs of which pulses come from the output of the input device 1.

With a small phase difference between the input signal at the input of the bandpass filter 2 and the output of the threshold device 4, short pulses will appear at the outputs of the first and second triggers 5 and 6, which open the first and second analog keys 7 and 8, and alternately will be formed at their midpoint Narrow positive and negative impulses following each other. After these pulses pass through an RC circuit formed by a resistor 9 and a capacitor 10, they will integrate and turn into a constant voltage close to zero. This voltage is supplied to the gate of the field-effect transistor 11, and its equivalent resistance, included in the frequency-determining circuit of the band-pass filter 2, tunes the filter 2 to the frequency of the input signal.

If for some reason the phase of the output or input signal changes, the duration of the pulses generated by analog keys 7 and 8 also changes, and if the phase of the output signal is ahead of the input phase, the duration of positive pulses will increase, and negative ones will decrease, if it is delayed, then vice versa .

After these pulses pass through the RC circuit, the gate voltage of the field-effect transistor 11 will be positive, the transistor will change the equivalent resistance, and the phase equality will be restored. The same happens if the gate voltage of the field effect transistor is negative.

Thus, there is a phase adjustment of the sinusoidal voltage of the claimed generator.

Using the proposed invention allowed to create a sinusoidal voltage generator with high phase stability of the output voltage.

Sources of information

1. P. Horwitz, W. Hill. The art of circuitry. M .: Mir, 1983, p. 275, fig. 4.2.6.c.

2. Certificate of the Russian Federation for utility model No. 18466, 2001, class. H 03 B 5/00 (prototype).

Claims (1)

A sinusoidal voltage generator comprising a series-connected input circuit, the input of which is the input of the device, a bandpass filter, an operational amplifier, the output of which is the output of the device, and a threshold element, characterized in that the first and second analog keys, the first and second triggers are additionally introduced into it , a resistor, a capacitor and a field effect transistor, connected by a drain and a source to the frequency-determining circuit of a band-pass filter, and by a gate through a capacitor to a common bus and through a resistor to the middle the point of the first and second analog keys connected in series between the positive and negative power sources of the device, and the control inputs of the keys are connected respectively to the outputs of the first and second triggers, the S-input of the first trigger is connected to the R-input of the second trigger and connected to the output of the threshold element, and the S-input of the second trigger is connected to the R-input of the first trigger and connected to the input of the bandpass filter.